1. Field of the Invention
The present invention relates to a dispenser for a dental viscous material, which is capable of simultaneously discharging desired amounts of respective viscous materials from a cartridge, where two kinds of viscous materials for the dental viscous material are respectively stored.
2. Description of the Conventional Art
As for the dental viscous material comprising the two kinds of the viscous materials, since a chemical reaction is generally generated by mixing both viscous materials, the viscous materials are respectively stored in different containers in general. Thus, when using such a dental viscous material, it is used by measuring the necessary amount of each viscous material in each container (the amounts of the two kinds of viscous materials are equal in many cases), putting these viscous materials on a kneading paper or in a container for mixing, and mixing and kneading these materials by a rod, a spatula or the like.
However, as for such the dental viscous material, the chemical reaction is generally generated immediately after mixing these materials. Thus, it is necessary to carry out quickly a series of works for measuring the viscous materials and mixing and kneading those. More particularly, when the viscous materials are measured, for example, a tube must be used as the container for storing the viscous material, and a paper, in which a graduation line for measuring a length is preprinted, must be used as the kneading paper for mixing and kneading the two kinds of the viscous materials. Further, when the amounts of the viscous materials are equal, the tubes for storing these materials have same diameters of discharging ports, and each tube is pressed so as to discharge these materials with same lengths by referring to the graduation of the kneading paper, to thereby measure the viscous materials. Further, when the amounts of the viscous materials are not equal, the tubes having the different diameters of the discharging ports are used to discharge the viscous materials with the same lengths, or the tubes having the same diameters of the discharging ports are used to discharge these materials with the different lengths. Therefore, there are problems that the measuring work is troublesome and needs much time. Further, in addition to such a measuring work, an operator such as a dentist, an oral hygienist or the like, must carry out a work for mixing and kneading the viscous materials on the kneading paper, while taking care that these materials are fully mixed and bubbles are not immixed. Thus, there are problems that such the work needs not only certain skill but also large force at the time of mixing and kneading since the viscous material has high viscosity.
For solving such the problems, present inventors have developed a viscous material storing cartridge for storing the dental viscous material comprising the two kinds of viscous materials, and a dispenser for simultaneously discharging desired amounts of respective viscous materials from the viscous material storing cartridges.
As the viscous material storing cartridge for storing the dental viscous material comprising the two kinds of viscous materials, for example, following cartridge has been proposed (refer to Japanese Patent Application Laid Open No. 2000-201951). It is a viscous material storing cartridge comprising two parallel cylindrical bodies having opening parts at rear ends and discharging ports at front ends, and having constant cross-sectional shapes of the inner faces. In this cartridge, the rear ends is round flange parts formed in different shapes according to the stored material, the front ends are respectively connected with connecting parts, the dental viscous materials which are used by mixing with predetermined ratio are stored inside the cylindrical bodies, and opening parts of the rear ends are closed with caps for pushing out the stored materials. Further, a nozzle mounting part is provided at the front end of the cartridge to mount and hold a rear end of nozzle at the discharging port, and this nozzle is for dispensing the dental viscous materials pushed out from the insides of the cylindrical bodies while mixing and kneading those with a mixing tool. Further, the following cartridge also has been proposed (refer to Japanese Patent Application Laid Open No. 2003-212278). It is a viscous material storing cartridge comprising a viscous material storing part, a rotary shutter, a rotary shutter holding means, and a mixing tool mounting part. In this cartridge, the viscous material storing part comprises two parallel cylindrical bodies having opening parts at rear ends and discharging ports at front ends, and having constant cross-sectional shapes of the inner surfaces, and viscous material pushing out members are respectively fit to these inner faces. The rotary shutter has a size capable of closing at least all the discharging ports of the viscous material storing part, and has a communication hole provided at a position corresponding to the discharging ports. The rotary shutter holding means is provided at the front end of the viscous material storing part, and rotatably holds the rotary shutter, where the communication holes of the rotary shutter and the discharging ports of the viscous material storing part can be changed between a communicated state and a closed state by this shutter. The mixing tool mounting part is provided for mounting the mixing tool, which mixes the viscous materials in each cylindrical part discharged from the communication holes.
Further, as the dispenser for simultaneously discharging desired amounts of each viscous material from the viscous material storing cartridges, for example, the following dispenser has been proposed (refer to Japanese Patent Application Laid Open No. 2000-308647). It is a dispenser for a dental viscous material comprising a housing, a guide shaft, a lever, an elastic member, a slide block, a pressing spring, a piston shaft, and a braking member. In this dispenser, the housing has a cartridge mounting part at a front end, which is for mounting the cartridge storing the dental viscous material. The guide shaft is supported slidably in frontward and rearward directions in a cavity of the housing, and has a lever engaging part at a predetermined position. The lever is mounted freely on the housing by the lever shaft, where one end is engaged with the lever engaging part of the guide shaft and another end is positioned at the outside of the housing. The elastic member is provided for engaging the housing and the guide shaft with the lever in order to return the guide shaft to the initial position. The slide block has a space opening at the lower side therein and has an external shape in a box shape matching to the shape of the cavity of the housing. A through hole for inserting the guide shaft in the frontward and rearward directions is provided at the slide block. An adjusting screw is screwed at a position being lower than a penetration hole for the guide shaft at a front sidewall. The pressing spring is for forwardly pressing a release plate and provided between a rear side wall member of the slide block and the release plate. The release plate has a hole formed having a little larger size than the thickness of the guide shaft and matching the shape of guide shaft. The release plate is mountable in a state inclining to an axis of the guide shaft by adjusting a backwardly extending length of the adjusting screw. The guide shaft is inserted into the hole. The piston shaft is fixed to the slide block and has an axis which is parallel to the axis of the guide shaft for pressing the viscous material in the cartridge from the rear side. The braking member is provided in the housing, and constantly presses the piston shaft by the elastic force.
By using such the viscous material storing cartridge or the dispenser for the dental viscous material, when the needed amounts of respective viscous materials of the dental viscous materials are measured or the viscous materials are mixed and kneaded, the problems of the troublesome or taking much time are solved. Further, the problems that the skill is necessary and the large force at the time of mixing and kneading is needed since the viscous material has the high viscosity are solved. However, as for such the dispenser for the dental viscous material, the following problems remain unsolved. After discharging the desired amount of the viscous material, the dispenser for the dental viscous material is often put on a work table or kept in a refrigerator or a rack in the states that the viscous material storing cartridge having the residual viscous material is mounted on the cartridge mounting part and a top end of the piston shaft is contacted with the viscous material pushing out member of the viscous material storing cartridge. In such a state, the lever for forwardly transferring the guide shaft is pushed upwardly from the housing by the elastic member. Then, the lever is accidentally pressed downwardly, such as that an object drops down from the upper side, a hand touches the lever during the dental treatment, or the lever is contacted with the rack or object when being kept in the refrigerator or the rack. Then, the trouble that the viscous material stored in the viscous material storing cartridge is discharged against will is caused.
Further, as for the slide block in which the piston shaft is fixed to press the viscous material pushing out member in the viscous material storing cartridge mounted on the cartridge mounting part, when an operation for pressing the lever is repeated, the slide block is gradually slid in the front direction in the cavity of the housing. In this case, by visually confirming the position of the slide block in the housing from the opening part at the lower part of the housing, a residual amount of the viscous material stored in the viscous material storing cartridge and an estimated amount of the viscous material discharged from the viscous material storing cartridge can be understood, so that it is convenient. However, when the lever is pressed, the opening part, from which the position of the slide block in the housing can be visually confirmed, is positioned at the lower side of the housing, so that, when pressing the lever actually, the opening part is hidden in a palm. Thus, in order to confirm the position of the slide block in the housing, an operator pressing the lever must once stop the work specially to reverse the housing by 180 degrees. Therefore, there is a problem that such operator pressing the lever cannot carry out the work in actuality while confirming the residual amount or the discharged amount of the viscous material.
Furthermore, when the viscous material storing cartridge mounted on the cartridge mounting part is removed after discharging the desired amount of the viscous material, the release plate is pressed against the pressing spring provided between the rear side wall member and the release plate, and the slide block is backwardly pressed while keeping the release plate perpendicular the axis of to the guide shaft, to thereby slide the piston shaft to the initial position, where the release plate is mountable in the inclining state with respect to the axis of the guide shaft. Then, the viscous material storing cartridge is removed from the cartridge mounting part. However, since the release plate and the slide block are positioned at the lower part of the housing, the housing must be reversed by 180 degrees when carrying out such the operation. Thus, there is a problem for actually operating it.